In patients with obstructive sleep apnea with uncontrolled hypertension that is not alleviated by medication, can the use of continuous positive airway pressure (CPAP) lower both diastolic and systolic blood pressure?

Clinical Bottom Line

In patients with obstructive sleep apnea and systemic hypertension that is not controlled by medication, the use of CPAP device can aid in decreasing blood pressure if obstructive sleep apnea is controlled. This is supported by two meta-analyses and a randomized controlled trial that showed clinically a decrease in both systolic and diastolic blood pressure in a standard 24-hour period. Further research is needed for longer-term health outcomes.

968 adults with OSA without major comorbidities drawn from 8 randomized controlled trials

Meta-Analysis

Key results

Patients with OSA and uncontrolled hypertension are likely to have substantial reduction in blood pressure with the use of the CPAP machine. Systolic BP (SBP) was reduced by 7.1 mmHg and diastolic BP (DBP) by 4.3 mmHg after controlling for OSA severity. In comparison, patients without baseline hypertension did not have a significant decrease in blood pressure. This information was collected during a single standard 24-hour period or single day office visit, hence limiting reproducibility. Patients with uncontrolled hypertension and OSA would have the greatest benefit from using a CPAP.

5 studies with a total of 359 patients with uncontrolled HTN. CPAP treatment measured after 24 hours.

Meta-Analysis

Key results

This study calculated the mean difference (MD) between ambulatory blood pressure monitoring (ABPM) recordings taken during 24-hr follow-up. The average duration that the CPAP was used in these patients ranged from 4.2 to 6 hours per night. In RCTs that used only the CPAP arm and in uncontrolled observational studies, there was a significant reduction in both 24-hr systolic and diastolic BP compared to pre-CPAP levels ([MD = −4.6 mm Hg (95% CI= −6.3 to −2.9, p < 0.001)], [MD = −2.9 mm Hg (95% CI = −4.4 to −1.3, p < 0.001)] respectively). CPAP had a favorable effect after 24-hr BP was recorded during follow-up compared to standard anti-HTN treatment with patients having both OSA and uncontrolled HTN.

Bakker’s meta-analysis included 968 adult patients with OSA that had no major comorbidities drawn from 8 RCTs. They divided the groups between therapeutic PAP (486 patients) and non-therapeutic control conditions (482 patients) over a standard 24-hr period. This study stated no financial conflict of interest and took into account independent (predictors such as age, gender, BMI at baseline, therapeutic PAP levels, AHI severity, and treatment duration) and dependent (outcomes such as all blood pressure data available) variables. This study demonstrated a clinically significant reduction in BP for patients having uncontrolled hypertension at baseline only, but not for patients having controlled hypertension.
The Verounis meta-analysis of RCTs and uncontrolled observational studies (n= 190 patients) showed significant reduction in blood pressure in patients with uncontrolled hypertension.
In the Martinez study, patients were randomly assigned to receive CPAP or no CPAP treatment. These patients, on average, were taking 3.8 antihypertensive drugs and had a mean apnea-hypopnea index (AHI) of 40.4 (SD, 18.9). There was a significant positive correlation between hours of CPAP use and decrease in a 24 hour period of mean BP, but further research is needed to assess longer-term health outcomes. No conflict of interest was reported.

Applicability

A continuous positive airway pressure device can reduce obstructive sleep apnea in patients with systemic hypertension that is not alleviated by medications within a 24-hour period. Both systolic and diastolic pressures have shown a clinically significant decrease within those 24 hours; however, more research is needed to determine longer-term outcomes.

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